This invention relates to a printer that prints on separate, cut sheets of paper. The printer may be separate from its data source, such as a computer, or may be installed within a machine such as a word processor.
Some printers, with either an automatic sheet-loading mechanism or a manual loading mechanism, have an initial sheet-setting function that automatically sets a sheet of paper at a predetermined initial printing position. For example, when an appropriate key (initial sheet-setting key) is pressed, a sheet on a sheet stack is fed forward into a printing mechanism to bring a preset top-of-page position at the printing head. A photo-sensor in the sheet path of a sheet loading mechanism detects the leading edge of the sheet and the sheet is fed a predetermined distance after detection. This assures a uniform starting position for printing on every sheet.
A problem occurs, however, when a sheet is already loaded in the printing mechanism. When a sheet is skewed in the printing mechanism, the operator releases pressure rollers from the sheet and manually aligns the leading and trailing edges of the sheet to set it at right angles. In this case, since the sensor cannot detect the leading edge of the sheet any more when the initial sheet-setting key is operated, the initial sheet-setting is not operated, instead the already loaded sheet is discharged from the printing mechanism. This makes the operator's sheet alignment futile. Therefore, after aligning the sheet, a special initial sheet-setting is required by, for example, manually rotating a platen or carefully operating a line feed switch. These operations are tedious, time consuming and, often, inaccurate.